Micromechanical component and method for producing the same

Abstract

A method of manufacturing a micromechanical component has a substrate ( 1 ), a movable sensor structure ( 6 ) in a micromechanical functional layer ( 5 ) located over the substrate; a first sealing layer ( 8 ) on the first micromechanical functional layer ( 5 ) which is at least partly structured; a second micromechanical functional layer ( 10 ) on the first sealing layer ( 8 ), which has at least one sealing function and is anchored at least partly in the first micromechanical functional layer ( 5 ); and a second sealing layer ( 8 ) on the second micromechanical functional layer ( 10 ). The sensor structure ( 6 ) is provided with trenches ( 7 ) whose width is not larger than a maximum trench width ( 66 ), which is sealable by the first sealing layer ( 8 ) in the form of plugs ( 9 ) which do not extend to the trench bottoms.

1. A method of manufacturing a micromechanical component, comprising:
 providing a substrate; 
 providing a first micromechanical functional layer on the substrate; 
 structuring the first micromechanical functional layer to include a sensor structure; providing a first sealing layer on the first micromechanical functional layer after the structuring of the first micromechanical functional layer, the first sealing layer having at least a covering function and being at least partially anchored in the first micromechanical functional layer; 
 structuring the first sealing layer; 
 providing a second micromechanical functional layer on the first sealing layer; 
 structuring the second micromechanical functional layer; and 
 making the sensor structure capable of vibrating; 
 providing a second sealing layer on the second micromechanical functional layer; 
 wherein a maximum trench width which is sealable by the first sealing layer in a form of a plurality of plugs is determined, the plurality of plugs not extending to a trench bottom; and 
 wherein the sensor structure is provided with a plurality of trenches, a first width of the plurality of trenches being not larger than the maximum trench width. 
 
   
   
     2. The method as recited in  claim 1 , further comprising:
 providing a comb structure including a plurality of intermeshing comb teeth in the sensor structure; 
 wherein a sum of a width of a comb tooth and twice a distance between adjacent intermeshing comb teeth is one of less than and equal to the maximum trench width. 
 
   
   
     3. The method as recited in  claim 1 , further comprising:
 providing a folded helical spring structure in the sensor structure; 
 wherein a distance between adjacent folds is equal to the maximum trench width, a maximum vibration amplitude of the sensor structure being equal to the number of folds times the maximum trench width. 
 
   
   
     4. The method as recited in  claim 2 , further comprising:
 providing a sacrificial layer on the substrate; 
 wherein the sacrificial layer and the first sealing layer are etched to make the sensor structure capable of vibrating. 
 
   
   
     5. The method as recited in  claim 4 , further comprising:
 structuring the first micromechanical functional layer to include a plurality of first passages extending to the sacrificial layer; and 
 structuring the second micromechanical functional layer to include a plurality of second passages extending to the first sealing layer, the plurality of second passages being connected to the plurality of first passages by a plurality of connection areas of the first sealing layer; 
 wherein the first sealing layer is etched to remove the plurality of connection areas using the plurality of second passages as a plurality of etch channels; 
 and wherein the etching of the sacrificial layer uses the plurality of first passages and the plurality of second passages as a plurality of etch channels, the plurality of first passages and the plurality of second passages being connected by the removal of the plurality of connection areas. 
 
   
   
     6. The method as recited in  claim 2 , further comprising:
 providing a buried polysilicon layer underneath one of the first micromechanical functional layer and the second micromechanical functional layer. 
 
   
   
     7. The method as recited in  claim 2 , wherein the first sealing layer and the second sealing layer are thinner than the first micromechanical functional layer and the second micromechanical functional layer. 
   
   
     8. The method as recited in  claim 5 , wherein at least one of the first sealing layer and the second sealing layer is provided by non-conforming deposition so that the plurality of first passages and the plurality of second passages are only plugged in an upper area. 
   
   
     9. The method as recited in  claim 5 , wherein the plurality of first passages and the plurality of second passages are designed as one of a plurality of trenches and a plurality of holes which narrow toward top. 
   
   
     10. The method as recited in  claim 2 , wherein at least one of the first micromechanical functional layer and the second micromechanical functional layer is a conductive material. 
   
   
     11. The method as recited in  claim 2 , wherein at least one of the first sealing layer and the second sealing layer is a dielectric material. 
   
   
     12. The method as recited in  claim 2 , wherein at least one printed conductor layer is provided on the second sealing layer. 
   
   
     13. The method as recited in  claim 2 , wherein a printed conductor structure is integrated into the second micromechanical functional layer. 
   
   
     14. A micromechanical component, comprising:
 a substrate; 
 a movable sensor structure in a first micromechanical functional layer situated above the substrate; 
 a first sealing layer on the first micromechanical functional layer, the first sealing layer being at least partially structured, the first sealing layer having at least one sealing function and being at least partially anchored in the first micromechanical functional layer; 
 a second micromechanical functional layer on the first sealing layer; and 
 a second sealing layer on the second micromechanical functional layer; wherein the movable sensor structure is provided with a plurality of trenches, a width of each trench being not larger than a maximum trench width, the plurality of trenches being sealable by the first sealing layer in a form of a first plurality of plugs, the first plurality of plugs not extending to a plurality of trench bottoms. 
 
   
   
     15. The micromechanical component as recited in  claim 14 , further comprising:
 a comb structure including a plurality of intermeshing comb teeth in the sensor structure; 
 wherein a sum of a width of a comb tooth and twice a distance between adjacent comb teeth is one of less than and equal to the maximum trench width. 
 
   
   
     16. The micromechanical component as recited in  claim 13 , further comprising:
 a folded helical spring structure in the sensor structure; 
 wherein a distance between adjacent folds is equal to the maximum trench width, a maximum vibration amplitude of the sensor structure being equal to a number of folds times the maximum trench width. 
 
   
   
     17. The micromechanical component as recited in  claim 14 , wherein:
 the movable sensor structure is located over a sacrificial layer situated on the substrate; and 
 the movable sensor structure is made movable by at least partly removing the sacrificial layer and the first sealing layer. 
 
   
   
     18. The micromechanical component as recited in  claim 17 , wherein:
 the first micromechanical functional layer includes a plurality of first passages extending to the sacrificial layer; 
 the second micromechanical functional layer includes a plurality of second passages extending to the first sealing layer; and 
 the plurality of first passages and the plurality of second passages are connected to each other by a plurality of removed connection areas of the first sealing layer. 
 
   
   
     19. The micromechanical component as recited in  claim 17 , further comprising:
 a buried polysilicon layer underneath the movable sensor structure between the sacrificial layer and the substrate. 
 
   
   
     20. The micromechanical component as recited in  claim 14 , wherein the first sealing layer and second sealing layer are thinner than the first micromechanical functional layer and the second micromechanical functional layer. 
   
   
     21. The micromechanical component as recited in  claim 18 , wherein at least one of:
 the first sealing layer includes a second plurality of plugs for sealing the plurality of first passages; and 
 the second sealing layer includes a third plurality of plugs for sealing the plurality of second passages. 
 
   
   
     22. The micromechanical component as recited in  claim 18 , wherein at least one of the plurality of first passages and the plurality of second passages are one of a plurality of trenches and a plurality of holes which narrow toward top. 
   
   
     23. The micromechanical component as recited in  claim 14 , wherein at least one of the first micromechanical functional layer and the second micromechanical functional layer is a conductive material. 
   
   
     24. The micromechanical component as recited in  claim 14 , wherein at least one of the first sealing layer and the second sealing layer is a dielectric material. 
   
   
     25. The micromechanical component as recited in  claim 14 , further comprising:
 at least one printed conductor layer provided on the second sealing layer. 
 
   
   
     26. The micromechanical component as recited in  claim 14 , wherein the second micromechanical functional layer includes a printed conductor structure. 
   
   
     27. The micromechanical component as recited in  claim 14 , wherein the second micromechanical functional layer includes a diaphragm structure. 
   
   
     28. The method as recited in  claim 10 , wherein the first micromechanical functional layer and the second micromechanical functional layer are manufactured from polysilicon. 
   
   
     29. The method as recited in  claim 11 , wherein the at least one of the first sealing layer and the second sealing layer is manufactured from silica. 
   
   
     30. The method as recited in  claim 12 , wherein the at least one printed conductor layer includes aluminum. 
   
   
     31. The micromechanical component as recited in  claim 23 , wherein the at least one of the first micromechanical functional layer and the second micromechanical functional layer is polysilicon. 
   
   
     32. The micromechanical component as recited in  claim 24 , wherein the at least one of the first sealing layer and the second sealing layer is silica. 
   
   
     33. The micromechanical component as recited in  claim 25 , wherein the at least one printed conductor layer includes aluminum.